• Proceedings of the SAREK Conference
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.551-556
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• 2008

This study analyzed operation characteristics of air-condition piping is made by quick disconnect coupling. Air-conditioning consists of central compressor 3HP capacity and R22 refrigerant. We experimented with two operation cycles of air-condition under the same environment; one is with quick disconnect coupling. The other is without quick disconnect coupling. As a result, we can observe whether the condensation temperature of former increased by about 3-5. Furthermore, COP decreased by about 10%.

• Journal of the Korean Regional Science Association
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• 제40권2호
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• pp.39-55
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• 2024

This study attempted to derive a plan for sustainable operate by identifying the status and operation condition of the community facilities of the Youth Jochiwon Project through case studies and interviews. Examining at the status and operation condition, 13 facilities are scheduled to be built in Jochiwon by 2025, but many facilities have not yet been prepared for specific operation plans. Second, the possibility of sustainable operation is positively evaluated based on creating jobs and profits through connection with other facilities and the introduction of paid system. Third, administrative support is being provided in various aspects, but there was a regret due to the limitation of the budget. It is expected that the function of health/welfare and leisure/culture can be strengthened for sustainable operation, support in term of administrative support is needed, and support and management function can be strengthened by utilizing the urban registration support center.

• Bulletin of the Korean Mathematical Society
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• 제41권3호
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• pp.493-505
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• 2004

We introduce certain local Thomsen condition in a 3-web and prove that it is equivalent to the equation a－(a－b)＝b in its corresponding loop, where we denote the loop operation additively for convenience and simplicity, even though the loop is neither associative nor commutative. Also we interpret such local Thomsen condition using orthogonality of chains in a web.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제6권3호
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• pp.36-43
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and breakage during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

• Proceedings of the KSR Conference
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2215-2222
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• 2010

Advanced EMU have been enhanced in terms of safe transport and maintainability. It is a new urban railway technology that enables an operation institution to cut repair and maintenance costs and customers to use convenient service at lower costs based on IT technology. If a development vehicle of Advanced EMU is completed, it will be used to test the entire advanced EMU system through sufficient performance check and reliability check prior to operation in commercial line. It will also verify efficiency, safety, punctuality and energy efficiency of transport. Accordingly, it is necessary to figure how to repair and maintain vehicles to enhance safety of Advanced EMU system in cooperation with operation during the period of comprehensive evaluation on the operation of a development vehicle in a test line. In this paper, we investigated the maintenance program of Advanced EMU on test operation in Dabul line. The test condition and operation environment of Advanced EMU in Daebul line was analyzed.

• International conference on construction engineering and project management
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.537-539
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• 2015

considerate operation is a major issue in the equipment-intensive operation. Identifying an optimal equipment combination is important to achieve low-energy operations. An Earthwork operation planning system, which measures the energy consumption of construction operations by taking into account construction equipments' engineering attributes (e.g., weight, capacity, energy consumption rate, etc.) and operation conditions (e.g., road condition, attributes of materials to be moved, geometric information, etc.), is essential to achieve the low-energy consumption. This study develops an automated computerized system which identifies an optimal earthmoving equipment fleet minimizing the energy consumption. The system imports a standard template of earthmoving operation model and compares numerous scenarios using alternative equipment allocation plans. It finds the fleet that minimizes the energy consumption by enumerating all cases using sensitivity analysis. A case study is presented to verify the validity of the system.

• Journal of Korean Society of Water and Wastewater
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• 제13권4호
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• pp.54-61
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• 1999

SBR process used to evaluate the removal of organics, nitrogen and phosphorus on the basis of a report of research on a precedence at various operation cycle and condition change. Effluent concentration of COD were 50mg/l, 50mg/l, 90mg/l respectively, The removal rates of COD were nearly over 95% at Run 1, 2 and 4. But at Run 3, Effluent concentration of COD was 255.0mg/l, The removal rate of COD was 87% at Run 3. As Oxic/Anoxic rate was fixed and operating cycle of Oxic/Anoxic was changed, the removal rates of T-N were 74.7%, 46.9%, 28.5%, 63.3% respectively at Run 1~4. The case of Run 1 was best result. The removal rates of T-P was appeared in proportion to T-N removal rates and rest of $NO_2-N$. The removal rates of T-P were 51.2%, 35.5%, 41.5%, 51.9% respectively. The removal rates of COD, T-N, T-P were influenced on the change of SBR operation cycle. As organic loading rate was $1.43kgCOD/m^3day$ and C/N ratio was 3.0, operation cycle of Run 1 was best condition of T-N removal rates and T-P removal.

• Transactions of the Korean Society of Mechanical Engineers
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• 제18권11호
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• pp.2913-2921
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• 1994

In SMA(shape memory alloy), the degradation by fatigue is one of the most important problems to be overcome, when SMA is used for robot-actuator material. The actuator is operated repeatitively for long time and its repeating operation develops the fatigue degradation of SMA. The fatigue degradation changes the transformation temperature and deformation behavior and results in inaccurate operation control of robot. Accordingly, the changing behavior of transformation temperature and deformation which results from repeating operation is to be investigated in advance and the scheme to resolve those problems have to be made for the design of actuator. In this study, the fatigue tests were carried out on SMA specimens prepared to have different condition of aging time and pre-strain with the direct-current heating-cooling method, which was a general method of operation in robot actuators. The behavior of transformation temperature and deformation were examined and analyzed in each specimen and the study was performed to establish the optimistic manufacturing condition of SMA against the fatigue degradation.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.773-780
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• 2012

The article presented is concerned with an evaluation of the corrosion behavior of SA-508 low alloy steel (LAS) and Type 309L stainless steel (SS) cladding of a reactor pressure vessel under the simulated primary water chemistry of a pressurized water reactor (PWR). The uniform corrosion and galvanic corrosion rates of SA-508 LAS and Type 309L SS were measured in three different control conditions: power operation, shutdown, and power operation followed by shutdown. In all conditions, the dissimilar metal coupling of SA-508 LAS and Type 309L SS exhibited higher corrosion rates than the SA-508 base metal itself due to severe galvanic corrosion near the cladding interface, while the corrosion of Type 309L in the primary water environment was minimal. The galvanic corrosion rate of the SA-508 LAS and Type 309L SS couple measured under the simulated power operation condition was much lower than that measured in the simulated shutdown condition due to the formation of magnetite on the metal surface in a reducing environment. Based on the experimental results, the corrosion rate of SA-508 LAS clad with Type 309L SS was estimated as a function of operating cycle simulated for a typical PWR.

• The Journal of the Korean dental association
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• 제17권2호통권117호
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• pp.129-135
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• 1979

This 27 year-old male patient had severe mandibular prognathism (right and left mesio-occlusion were 0.4㎝ and 1.2㎝ , respectively). He had good oral health relatively exception of missing teeth. We examined all of his oral and skeletal status with full mouth x-ray taking, study model, and cephalogram. His general condition was good but above examination indicated the surgical operation for the mandibular prognathism. His laboratory tests were within normal limits. We determined surgical operation which was done by extraoral approach bilaterally. Incisions were made bilaterally 1.5㎝ beneath the inferior border of the mandible in the selected area and then the inferior border of the ascending rami was exposed. Retracting the periosteum to the lingual and buccal a slight amount, the cut in the bone was performed by use of bone drill. Avoiding T.M.J. troubles, the proximal segmant was not fixed to anterior segment, being in overlapping state buccally, in order to expect a natural healing by the environmental muscles and ligaments. We had immobilization with intermaxillary fixation by using the multiple Stout's method. He was discharged 17 days after operation. His general condition and operation results were good and satisfactory.